Microencapsulated carotenoids from orange sweet potato: Degradation kinetics and physicochemical properties

The use of natural pigments in the food industry has increased due to their health benefits. Carotenoids are natural pigments that carry the disadvantage of sensitivity to temperature, light and the presence of enzymes and oxygen. Microencapsulation technology is widely used to protect these compounds against degradation, preserving their physicochemical characteristics. The research objective was to obtain the kinetics of carotenoid degradation of a microencapsulated extract of orange-fleshed sweet potato (Ipomoea batatas L.) and to establish its physicochemical properties. The sweet potato extract was obtained using ultrasound and then microencapsulated by spray drying using maltodextrin as the wall material. The microencapsulate obtained was subjected to degradation kinetics at 30, 40 and 50°C. Carotenoid quantification analysis, colour, rehydration properties, antioxidant capacity, Fourier-transform infrared (FTIR) and RAMAN spectroscopy and microstructural characterisation were performed on the microencapsulated carotenoids. From the kinetic analysis, the activation energy of the sweet potato extract was 16.31 kJ/mol while that of the microencapsulated sweet potato extract was 10.27 kJ/mol. Thus, it can be concluded that the microencapsulation process improved the stability of carotenoids subjected to thermal conditions. FTIR and RAMAN spectra confirmed the microencapsulation of the carotenoids. The microencapsulated powder showed a hygroscopicity of 0.22 g/100 g, wettability of 49 s and high solubility. The results obtained in the kinetics are a useful tool to predict losses during the process of heating the carotenoids from sweet potato, thus allowing improvement and selection of the products to which this powder can be applied, in either thermal or cold processes.